A brief description about field responsive fluids and their properties are described. Magnetorheological (MR) fluids are liquid materials whose properties can be controlled by the execution of an external magnetic field. These rheological changes are reversible and dependent on the strength of an excitation magnetic field. In this book, customized test equipment was constructed and fabricated, while the magnetic circuit design was analyzed using finite element method. The equipment was capable of varying the magnetic field strengths. Combinations of process parameters of initial gap size, applied current and squeeze speed were used in the experiments. Results, mainly in terms of stress-strain relationships were presented and discussed. In addition, the behaviour of MR fluids was found to be dependent on the relative movement between the solid magnetic particles and the carrier fluid in squeeze mode. Eventually, the understanding of the behaviour of such fluids, together with recent progress in the development of MR fluids, has convinced researchers and engineers that MR devices are among the most promising devices for a large number of applications in various technological fields.